Diadenosine polyphosphate or derivatives thereof have physiological functions which include promoting DNA synthesis in BHK cells suffering from G1 inhibition as disclosed in F. Grummt, Pro. N.A.S., 75, 371 (1978), inhibiting phosphorylation as disclosed in P. F. Maness et al., J. Biol. Chem., 258, 4055 (1983), and inhibiting platelet aggregation as disclosed in M. J. Harrison et al., FEBS Letters, 54, 57 (1975). Thus, nucleoside polyphosphates (hereinafter referred to simply as NpnN') such as diadenosine polyphosphate or nucleoside polyphosphates (hereinafter referred to simply as pnN) and derivatives thereof are known for their use as drugs and starting materials therefor.
Regarding methods for obtaining this diadenosine polyphosphate or derivatives thereof, O. Goerlich et al., Eur. J. Biochem., 126, 135 (1982) reports that diadenosine tetraphosphate is synthesized from adenosine-5'-triphosphate (hereinafter referred to simply as ATP) while dideoxyadenosine tetraphosphate, which is a derivative of diadenosine tetraphosphate, is synthesized from 2'-deoxyadenosine-5'-triphosphate, which is a derivative of ATP. These products are synthesized by using various aminoacyl-tRNA synthetases such as lysyl-tRNA synthetase, histidyl-tRNA synthetase and phenylalanyl-tRNA synthetase each originating in Escherichia coli, lysyl-tRNA synthetase and phenylalanyl-tRNA synthetase each originating in yeasts, phenylalanyl-tRNA synthetase originating in Fusarium and phenylalanyl-tRNA synthetase originating in sheep hepatic cells.
In the above-mentioned method wherein ATP or a derivative thereof is reacted with an amino acid under the catalytic action of each aminoacyl-tRNA synthetase to thereby synthesize NpnN', incubated microorganisms or hepatic cells are disrupted and the target enzyme is purified to obtain the aminoacyl-tRNA to be used as a catalyst. However, since microorganisms or cells occurring in nature contain only an extremely small amount of the aminoacyl-tRNA synthetase, there is a disadvantage that a large amount of microorganisms must be incubated or a large amount of cells must be prepared for producing the NpnN'.
Another method for synthesizing NpnN' by reacting ATP or its derivative with adenosine-5'-phosphosulfate (hereinafter referred to simply as APS) under the catalytic action of diadenosine tetraphosphate phosphorylase (hereinafter referred to simply as Ap.sub.4 A phosphorylase) was proposed by A. Guranowski et al., Biochemistry, 27, 2959 (1988). The method wherein APS is used suffers from some problems such that the APS starting material is unstable and expensive. Moreover, the ATP or its derivative (ATP is used in the above reference) is converted into NpnN' (ApnN' is used in the above reference) only at a low rate, which causes practical problems for synthesizing the NpnN' from ATP or a derivative thereof.